1. Field of the Invention
This invention relates to a recording or reproducing apparatus and more particularly to an apparatus using a flexible disc as a recording medium and having a stabilizer member which is arranged to confront a recording or reproducing head across the disc for the purpose of obtaining an adequate opposed state of the disc and the head by stabilizing the portion of the disc passing by the head.
2. Description of the Prior Art
Generally, in the recording or reproducing apparatus of the above-stated kind, when a recording or reproducing head (hereinafter referred to as the head) is brought close to a disc or the recording medium rotating at a high speed, an air stream is generated by the disc rotation. Then, this air stream hinders the head and the disc from being kept in an adequately opposed state. This results in a detriorated recording or reproduction performance.
To solve this problem, it has come to be practised during recent years to have a stabilizer member opposed to the head across the disc as shown in FIG. 1 of the accompanying drawings. With the stabilizer member thus arranged on the opposite side of the disc, the rotation of the disc brings about another air stream between the disc and the stabilizer member as well as the air stream between the disc and head. It has been thus attempted to obtain an adequate opposed state between the head and the disc by virtue of the arrangement to have these air streams on both sides of the disc.
Referring to FIG. 1, the illustration includes a flexible disc 1 which is employed as a recording medium and is, for example, a magnetic disc. A center core 2 which is made of a plastic material is attached to the middle part of the disc 1. The center core 2 is provided with a center hole 2a which is arranged to be fitted on the spindle 3a of a disc rotating motor 3. With the center core thus mounted on the spindle 3a, the motor rotates, for example, in the direction of arrow A at a given speed of, say, 3,600 rpm in the case of a still picture recording or reproducing apparatus. A recording or reproducing head 4 is, for example, a magnetic head and is carried by a head carriage 7 to be shiftable radially over the disc 1 as indicated by an arrow B in FIG. 1. With the head arranged in this manner, recording tracks are formed on the recording surface of the disc 1 either in a concentrical shape or in a helical shape. A stabilizer member 5 is arranged to confront the head 4 via the disc 1 for the purpose of stabilizing the disc 1 as mentioned above. The details of the arrangement are as shown in FIG. 2. To avoid collision with the head 4, the member 5 is provided with a recessed groove 5c which is formed in a rectangular sectional shape with a fixed opening width and extends according to the moving passage of the head 4 in the direction of arrow B as shown in FIG. 1. The disc confronting surface of the stabilizer member 5 is thus divided by the groove 5c into an upstream side confronting face 5a and a downstream side confronting face 5b relative to the rotating direction A of the disc 1. A back plate 6 which is provided as necessary has a slot 6a. The slot 6a allows the head 4 to protrude toward the disc 1 through the slot.
The stabilizer member 5 is closely opposed to the upper surface of the disc 1 which is on the side opposite to the recording surface of the disc 1 as shown in FIG. 2. Meanwhile, the head 4 is arranged to have its fore end either slightly protrude inside of the recessed groove 5c of the stabilizer member 5 or flush with the above-stated disc confronting faces 5a and 5b in such a way as to be also confronting the recording surface of the disc 1. The back plate 6 is also opposed to the recording surface of the disc 1 at a distance which is greater than a distance at which the stabilizer member 5 confronts the upper surface of the disc 1.
When the disc 1 is rotated in the direction of arrow A under this condition, an air stream which is brought about between the disc 1 and the upstream side confronting face 5a of the stabilizer member 5 by the rotation of the disc 1 produces positive pressure. A portion of the disc 1 located at this part is pushed downward by the positive pressure. Meanwhile, negative pressure is produced between the disc 1 and the downstream side confronting face 5b. The negative pressure pulls the disc 1 toward the stabilizer member 5 against the rigidity of the disc. As a result, as shown in FIG. 2, the disc 1 is apt to come into contact with the downstream side confronting face 5b. Then, if the two come into contact, the opposed state between the head 4 and the disc 1 becomes unstable. Under this condition, the confronting face 5b of the stabilizer member 5 tends to be abrased by an abrasive, such as SiO.sub.2, TiO.sub.2 or the like, included in the binder used for the magnetic layer of the disc 1. In that event, the abrasive which is peeled off and freed from the disc 1 sticks to the flaws in the stabilizer member 5 to deteriorate thereby the surface condition of the stabilizer member 5. The deteriorated surface of the member 5 comes to impose an abnormal load on the motor 3 which is rotating the disc 1. This eventually causes an abnormal operation of the servo-mechanism of the apparatus. Furthermore, the abrasive sticking to the stabilizer member 5 accelerates the peeling off of the abrasive remaining in the binder of the magnetic layer of the disc 1. The abrasive which is thus freed from the disc 1 then comes close to the head 4 to accelerate the wear of the head. These troubles all stem from the contact brought about between the disc 1 and the stabilizer member 5 by the above-stated negative pressure.